Phason elasticity in entropic quasicrystals

The equilibrium quasicrystal phase of a two-dimensional two-component Lennard-Jones atomic system and two different ensembles of random tilings (binary and uncontrained) are analyzed by means of Monte Carlo simulations. We find that the quasicrystal phase in the atomic system is well described by the random-tiling model. Despite the nonzero configurational entropy density, the phason fluctuations are found not to destroy the quasi-long-range translational order in this phase, in agreement with conjectured square-gradient phason elasticity. Nearly identical, temperature-independent, reduced, phason elastic constants are determined in all three cases.